buy

zakoupit
[baɪ] (ekon.) "I will need to buy two tickets for the shuttle bus to Narita." (Budu muset zakoupit dva lístky na kyvadlový autobus do Narita.)

kupovat
[baɪ] (ekon.) "All my money is gone and I have nothing to buy food with." (Všechny mé peníze jsou pryč a já nemám za co kupovat jídlo.)
"She said that she had no money; yet, she would throw parties and buy herself expensive clothes and cosmetics." (Ona říkala, že nemá žádné peníze a přesto pořádala večírky a kupovala si drahé oblečení a kosmetiku.)

koupit
[baɪ] (ekon.) "There are some things you can't buy with money." (Jsou věci, které nelze koupit za peníze.)
"They bought a new house." (Koupili nový dům.)
"How much did you buy the car for?" (Za kolik jsi koupil to auto?)
"We'll buy you some shorts at the weekend, but meanwhile you'll just have to wear your long trousers." (O víkendu ti koupíme nějaké kraťasy, ale zatím holt budeš muset nosit dlouhé kalhoty.)

koupit si
[baɪ] (ekon.) "I'll buy some paperbacks at the airport." (Já si koupím nějaké knížky na letišti.)

pozvat na ...
[baɪ] (ekon.) co do restaurace koho, např. "I'd like to buy him lunch." (Chtěl bych ho pozvat na oběd.)

skočit na ...
[baɪ] uvěřit něčemu, např. "She'll never buy that story about you getting lost!" (Ona ti nikdy neskočí/nenaletí na tu tvou báchorku o tvém ztracení!)